import {
	type ButtonInteraction,
	type AnySelectMenuInteraction,
	type ModalSubmitInteraction,
	ButtonBuilder,
	StringSelectMenuBuilder,
	UserSelectMenuBuilder,
	RoleSelectMenuBuilder,
	ChannelSelectMenuBuilder,
	MentionableSelectMenuBuilder,
	ModalBuilder,
} from "discord.js";
import type { Option, InferOptions } from "./options";
import type { Middleware, ErrorHandler, Afterware } from "./commands";
import { CustomIdTooLong } from "./errors";

export type KittenComponentInteraction =
	| ButtonInteraction
	| AnySelectMenuInteraction
	| ModalSubmitInteraction;

export interface KittenComponentConfig<
	I extends KittenComponentInteraction,
	O extends Record<string, Option<any, any>>,
	Ctx = any,
	Res = unknown,
> {
	options?: O;
	onError?: ErrorHandler<I, Ctx>;
	run: (interaction: I, args: InferOptions<O>, ctx: Ctx) => Promise<Res> | Res;
}

/**
 * handler for routing interactive discord components.
 * automatically encodes your typed parameters into the `customId` to persist
 * state across interactions.
 */
export class KittenComponent<
	I extends KittenComponentInteraction = KittenComponentInteraction,
	O extends Record<string, Option<any, any>> = Record<string, Option<any, any>>,
	Ctx = any,
	Res = unknown,
> {
	type = "component" as const;

	constructor(
		public name: string,
		public config: KittenComponentConfig<I, O, Ctx, Res>,
		public middlewares: Middleware<any, any, any>[] = [],
		public errorHandlers: ErrorHandler<any, any>[] = [],
		public afterwares: Afterware<any, any, any>[] = [],
	) {}

	/**
	 * safely serializes your component's arguments into a discord-compatible custom ID.
	 *
	 * @throws {CustomIdTooLong} if the generated custom ID exceeds discord's 100 character limit.
	 * @returns a custom ID string that encodes the component name and its options' values.
	 */
	id(
		...[args]: {} extends InferOptions<O> ? [args?: InferOptions<O>] : [args: InferOptions<O>]
	): string {
		const keys = Object.keys(this.config.options || {});
		const values = keys.map((key) => encodeURIComponent(String((args as any)?.[key] ?? "")));
		const customId = [this.name, ...values].join(":");

		if (customId.length > 100) throw new CustomIdTooLong(this.name, customId.length);

		return customId;
	}

	/**
	 * parses the raw custom ID string payload back into typed arguments.
	 */
	parseArgs(customId: string): InferOptions<O> {
		const [, ...parts] = customId.split(":");
		const keys = Object.keys(this.config.options || {});
		const parsed: Record<string, any> = {};

		keys.forEach((key, index) => {
			const rawVal = parts[index];
			if (rawVal === undefined) return;

			const val = decodeURIComponent(rawVal);
			const opt = this.config.options?.[key];

			if (opt?.type === "boolean") parsed[key] = val === "true";
			else if (opt?.type === "integer" || opt?.type === "number") parsed[key] = Number(val);
			else parsed[key] = val === "" ? undefined : val;
		});

		return parsed as InferOptions<O>;
	}

	/**
	 * generate a pre-configured discord.js `ButtonBuilder` instance.
	 */
	button(
		this: KittenComponent<ButtonInteraction, O, Ctx, Res>,
		...[args]: {} extends InferOptions<O> ? [args?: InferOptions<O>] : [args: InferOptions<O>]
	): ButtonBuilder {
		return new ButtonBuilder().setCustomId(this.id(args as any));
	}

	/**
	 * generate a pre-configured discord.js `StringSelectMenuBuilder` instance.
	 */
	stringSelectMenu(
		this: KittenComponent<AnySelectMenuInteraction, O, Ctx, Res>,
		...[args]: {} extends InferOptions<O> ? [args?: InferOptions<O>] : [args: InferOptions<O>]
	): StringSelectMenuBuilder {
		return new StringSelectMenuBuilder().setCustomId(this.id(args as any));
	}

	/**
	 * generate a pre-configured discord.js `UserSelectMenuBuilder` instance.
	 */
	userSelectMenu(
		this: KittenComponent<AnySelectMenuInteraction, O, Ctx, Res>,
		...[args]: {} extends InferOptions<O> ? [args?: InferOptions<O>] : [args: InferOptions<O>]
	): UserSelectMenuBuilder {
		return new UserSelectMenuBuilder().setCustomId(this.id(args as any));
	}

	/**
	 * generate a pre-configured discord.js `RoleSelectMenuBuilder` instance.
	 */
	roleSelectMenu(
		this: KittenComponent<AnySelectMenuInteraction, O, Ctx, Res>,
		...[args]: {} extends InferOptions<O> ? [args?: InferOptions<O>] : [args: InferOptions<O>]
	): RoleSelectMenuBuilder {
		return new RoleSelectMenuBuilder().setCustomId(this.id(args as any));
	}

	/**
	 * generate a pre-configured discord.js `ChannelSelectMenuBuilder` instance.
	 */
	channelSelectMenu(
		this: KittenComponent<AnySelectMenuInteraction, O, Ctx, Res>,
		...[args]: {} extends InferOptions<O> ? [args?: InferOptions<O>] : [args: InferOptions<O>]
	): ChannelSelectMenuBuilder {
		return new ChannelSelectMenuBuilder().setCustomId(this.id(args as any));
	}

	/**
	 * generate a pre-configured discord.js `MentionableSelectMenuBuilder` instance.
	 */
	mentionableSelectMenu(
		this: KittenComponent<AnySelectMenuInteraction, O, Ctx, Res>,
		...[args]: {} extends InferOptions<O> ? [args?: InferOptions<O>] : [args: InferOptions<O>]
	): MentionableSelectMenuBuilder {
		return new MentionableSelectMenuBuilder().setCustomId(this.id(args as any));
	}

	/**
	 * generate a pre-configured discord.js `ModalBuilder` instance.
	 */
	modal(
		this: KittenComponent<ModalSubmitInteraction, O, Ctx, Res>,
		title: string,
		...[args]: {} extends InferOptions<O> ? [args?: InferOptions<O>] : [args: InferOptions<O>]
	): ModalBuilder {
		return new ModalBuilder().setTitle(title).setCustomId(this.id(args as any));
	}
}